Remove egm96

[Akxe]

When testing, I noticed that when bundled, the egm96 library is 2.5mb in size. There must be a better way to convert to the correct output without being the 99% of the library size...

[JuanIrache]

I see the following options:

• We move it to a separate dependency. Downside: It weighs the same after npm installing gopro-telemetry
• We rely on some API for altitude corrections. Downside: We lose offline functionality, and have to rely on third parties
• We let the user optionally provide an egm96 data file if they want altitude corrections (might be the simplest option)
• A combination of the above
• We disable altitude corrections altogether (I would rule this out)

[Akxe]

I like to option that user might provide the library on its own.

I see two options:

• We declare egm96-universal as an optional peer dependency; we could then use it only when the user installs it on his own.
• We declare a new option, seaLevelCorrection, that would do the same thing as now...

I do, however see a problem if the user is not aware of the option to provide seaLeveCorrection fn/library he would not know how to fix it... A warning could do it, but I am not sure that that would be a good fix either.

[JuanIrache]

I like the optional peer dependency route. Then in processGPS5.js we only proceed to the condition around line 45 if the library is present. Maybe print a warning if egm96-universal is missing. The warning can be avoided by setting the ellipsoid option to true and geoidHeight to false

[Akxe]

Just as I finish types for the library I will look into making the dependency optional and let you do the warning :)